diff --git a/doc/todo/extern b/doc/todo/extern
index 9be8f2b..cb42a07 100644
--- a/doc/todo/extern
+++ b/doc/todo/extern
@@ -21,3 +21,6 @@ to have. This means I won't code them, so somebody can code them.
       x intervalls
       x pre-/post exec
    o (X)dialog based
+
+- add option ("run_only_once") to prevent ccollect to run twice
+  (per source/general)